Thermodynamics is a science and, more importantly, an engineering
tool used to describe processes that involve changes in temperature,
transformation of energy, and the relationships between heat and
work. It can be regarded as a generalization of an enormous body of
empirical evidence1.1. It is extremely
general: there are no hypotheses made concerning the structure and
type of matter that we deal with. It is used to describe the
performance of propulsion systems, power generation systems, and
refrigerators, and to describe fluid flow, combustion, and many
other phenomena.

The focus of thermodynamics in aerospace engineering is on the
production of work, often in the form of kinetic energy (for example
in the exhaust of a jet engine) or shaft power, from different
sources of heat. For the most part the heat will be the result of
combustion processes, but this is not always the case. The course
content can be viewed in terms of a ``propulsion chain'' as shown in
Figure 1.1, where we see a progression from
an energy source to useful propulsive work (thrust power of a jet
engine). In terms of the different blocks, Parts I
and II are mainly about how to progress from the
second block to the third, Part III takes us from
the third to the fourth, and a chapter in Part IV takes
us from the first to the second. We will start with the progression
from heat to work, examples of which are given in
Figure 1.2.